Browsing by Author "Robinson, A."

Now showing items 1-18 of 18

    • The appearance of broad H alpha in BL Lacertae 

      Corbett, E.A.; Robinson, A.; Axon, D.J.; Hough, J.; Jeffries, R.D.; Thurston, M.R.; Young, S. (1996)
      We present optical spectropolarimetry confirming Vermeulen et al.'s recent discovery of a broad Hα emission line in BL Lacertae. This feature, which is present at about the same strength in spectra taken two days apart, ...

    • The contribution from scattered light to quasar galaxy hosts 

      Young, S.; Axon, D.J.; Robinson, A.; Capetti, A. (2009)
      We present models representing the scattering of quasar radiation off free electrons and dust grains in geometries that approximate the structure of quasar host galaxies. We show that, for reasonable assumptions, scattering ...

    • Equatorial scattering and the structure of the broad-line region in Seyfert nuclei: evidence for a rotating disc 

      Smith, J.E.; Robinson, A.; Young, S.; Axon, D.J.; Corbett, E.A. (2005)
      We present detailed scattering models confirming that distinctive variations in polarization across the broad Hα line, which are observed in a significant fraction of type 1 Seyfert galaxies, can be understood in terms of ...

    • Highly polarized structures in the near-nuclear regions of Cygnus A: intrinsic anisotropy within the cones 

      Tadhunter, C.N.; Sparks, W.; Axon, D.J.; Bergeron, L.; Jackson, N.; Packham, C.; Hough, J.; Robinson, A.; Young, S. (2000)
      We present near-IR imaging polarimetry observations of the nucleus of Cygnus A, taken with the NICMOS camera of the HST at a wavelength of 2.0μm. These maps reveal a highly collimated region of polarized emission straddling ...

    • Monitoring the Ha Line in BL Lacertae - Evidence for an Accretion Disk 

      Corbett, E.A.; Robinson, A.; Hough, J.; Axon, D.J. (Astronomical Society of the Pacific, 1999)
      We present new spectroscopic observations of the recently discovered broad Ha line in BL Lacertae. These data, obtained over a period of 30 months, indicate that the line equivalent width is anti-correlated with the continuum ...

    • Nicmos polarimetry of "polar-scattered" seyfert 1 galaxies 

      Batcheldor, D.; Robinson, A.; Axon, D. J.; Young, S.; Quinn, S.; Smith, J. E.; Hough, J.; Alexander, D. M. (2011-09-01)
      The nuclei of Seyfert 1 galaxies exhibit a range of optical polarization characteristics that can be understood in terms of two scattering regions producing orthogonal polarizations: an extended polar scattering region ...

    • Optical Spectropolarimetry of Broad Line Active Galaxies 

      Giannuzzo, M.E.; Corbett, E.A.; Robinson, A.; Young, S.; Hough, J.; Axon, D.J. (Astronomical Society of the Pacific, 1999)
      We present new optical spectropolarimetry of two bright type 1 AGNs. The observations are part of a project on broad line active galaxies in which, through data analysis and modelling, we aim to identify the polarization ...

    • Parsec-scale imaging of the radio-bubble Seyfert galaxy NGC 6764 

      Kharb, P.; Hota, A.; Croston, J.H.; Hardcastle, M.J.; O'Dea, C.P.; Kraft, R.P.; Axon, D.J.; Robinson, A. (2010)
      We have observed the composite active galactic nucleus (AGN)-starburst galaxy NGC 6764 with the Very Long Baseline Array at 1.6 and 4.9 GHz. These observations have detected a "core-jet" structure and a possible weak ...

    • Powering the Broad H alpha Line in BL Lacertae 

      Corbett, E.A.; Robinson, A.; Hough, J.; Young, S.; Axon, D.J. (Astronomical Society of the Pacific, 1996)

    • The profiles of polarized broad Hα lines in radio galaxies 

      Corbett, E.A.; Robinson, A.; Axon, D.J.; Young, S.; Hough, J. (1998)
      We present spectropolarimetric observations of seven broad-line radio galaxies. We find significantly polarized broad Hα emission in four objects including two, Arp 102B and 3C 390.3, which have double-peaked line profiles. ...

    • The rotating wind of the quasar PG 1700+518 

      Young, S.; Axon, D.J.; Robinson, A.; Hough, J.; Smith, J.E. (2007)

    • Searching for the hidden broad-line region in Centaurus A 

      Alexander, D.M.; Hough, J.; Young, S.; Bailey, J.; Heisler, C.A.; Lumsden, S.; Robinson, A. (1999)
      We present the first near-infrared (K-band) spectropolarimetric observations of the nuclear region of Centaurus A. Although the data are of high signal-to-noise ratio, polarized broad Brγ is not detected and we place a 3σ ...

    • A Seyfert Nucleus in BL Lacertae 

      Axon, D.J.; Corbett, E.A.; Robinson, A.; Hough, J. (Astronomical Society of the Pacific, 1999)
      We have obtained spectroscopic observations of the broad Ha line in BL Lacertae over a period of 30 months. These data show that the line equivalent width is anti-correlated with the continuum flux implying that the broad ...

    • A Seyfert-like nucleus concealed in BL Lacertae? 

      Corbett, E.A.; Robinson, A.; Axon, D.J.; Hough, J. (2000)
      We present a series of new spectroscopic observations of BL Lacertae. The observations were obtained over a period of 30 months and sample the violent continuum flare of 1997 June–August. The equivalent width of the recently ...

    • A spectropolarimetric atlas of Seyfert 1 galaxies 

      Smith, J.E.; Young, S.; Robinson, A.; Corbett, E.A.; Giannuzzo, M.E.; Axon, D.J.; Hough, J. (2002-09)

    • Spectropolarimetric evidence for a kicked supermassive black hole in the quasar E1821+643 

      Robinson, A.; Young, S.; Axon, D.J.; Kharb, P.; Smith, J.E. (2010)
      We report spectropolarimetric observations of the quasar E1821+643 (z = 0.297), which suggest that it may be an example of gravitational recoil due to anisotropic emission of gravitational waves following the merger of a ...

    • Spitzer MID-IR spectroscopy of powerful 2Jy and 3CRR radio galaxies. II : Agn power indicators and unification 

      Dicken, D.; Tadhunter, C.; Morganti, R.; Robinson, A.; Magagnoli, M.; Kharb, P.; Ramos Almeida, C.; Mingo, B.; Hardcastle, M.J.; Nesvadba, N. P. H.; Singh, V.; Kouwenhoven, M. B. N.; Rose, M.; Spoon, H.; Inskip, K. J.; Holt, J. (2014-06-20)
      It remains uncertain which continuum and emission line diagnostics best indicate the bolometric powers of active galactic nuclei (AGNs), especially given the attenuation caused by the circumnuclear material and the possible ...

    • A time-variable scattered component to broad Hα in the Seyfert 1 galaxy Mrk 509 

      Young, S.; Corbett, S.A.; Giannuzzo, M.E.; Hough, J.; Robinson, A.; Bailey, J.; Axon, D.J. (1999)
      We present optical spectropolarimetry data for the Seyfert 1 galaxy Mrk 509 for three epochs: 1996 August and 1997 May and August. We confirm previous findings that broad Hα has a significantly greater width in the polarized ...